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 A002748 Sum of logarithmic numbers. (Formerly M0923 N0347) 2
 1, 2, 3, 26, 13, 1074, -1457, 61802, 7929, 4218722, -6385349, 934344762, -5065189307, 141111736466, 235257551943, 23219206152074, -97011062913167, 11887164842925762, -91890238533000461, 4819930221202545242, -14547510704199530499, 1184314832978574919922 (list; graph; refs; listen; history; text; internal format)
 OFFSET 0,2 REFERENCES J. M. Gandhi, On logarithmic numbers, Math. Student, 31 (1963), 73-83. N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence). N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence). LINKS J. M. Gandhi, On logarithmic numbers, Math. Student, 31 (1963), 73-83. [Annotated scanned copy] FORMULA E.g.f.: F(x)/exp(x)/x where F(x) is o.g.f. for A000203(). - Vladeta Jovovic, Feb 09 2003 MAPLE A002748 := proc(n) local f1, f2 ; f1 := add(numtheory[sigma](i)*x^(i-1), i=1..n+1) ; f2 := add((-x)^i/i!, i=0..n+1) ; n!*coeftayl(f1*f2, x=0, n) ; end: seq(A002748(n), n=0..25) ; # R. J. Mathar, Oct 22 2007 MATHEMATICA f1[n_] := Sum[DivisorSigma[1, i]*x^(i-1), {i, 1, n+1}]; f2[n_] := Sum[(-x)^i/i!, {i, 0, n+1}] ; a[n_] := n!*SeriesCoefficient[f1[n]*f2[n], {x, 0, n}]; Table[a[n], {n, 0, 21}] (* Jean-François Alcover, Jan 17 2014, after R. J. Mathar *) CROSSREFS Cf. A002750. Sequence in context: A109586 A060371 A130975 * A056004 A032812 A099006 Adjacent sequences:  A002745 A002746 A002747 * A002749 A002750 A002751 KEYWORD sign,easy AUTHOR EXTENSIONS More terms from Jeffrey Shallit More terms from R. J. Mathar, Oct 22 2007 STATUS approved

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Last modified September 19 15:18 EDT 2019. Contains 327198 sequences. (Running on oeis4.)